Ribulose 5-phosphate can alternatively undergo a series of isomerizations as well as transaldolations and transketolations that result in the production of other pentose phosphates as well as fructose 6-phosphate and glyceraldehyde 3-phosphate (both intermediates in glycolysis).

[1] The formation of R5P is highly dependent on the cell growth and the need for NADPH (Nicotinamide adenine dinucleotide phosphate), R5P, and ATP (Adenosine triphosphate).

It is a crucial source for NADPH generation for reductive biosynthesis[3] (e.g. fatty acid synthesis) and pentose sugars.

[2] During rapid cell growth, higher quantities of R5P and NADPH are needed for nucleotide and fatty acid synthesis, respectively.

Glycolytic intermediates can be diverted toward the non-oxidative phase of PPP by the expression of the gene for pyruvate kinase isozyme, PKM.

PKM creates a bottleneck in the glycolytic pathway, allowing intermediates to be utilized by the PPP to synthesize NADPH and R5P.

[2] R5P and its derivatives serve as precursors to many biomolecules, including DNA, RNA, ATP, coenzyme A, FAD (Flavin adenine dinucleotide), and histidine.

During the fifth step of pyrimidine nucleotide synthesis, PRPP covalently links to orotate at the one-position carbon on the ribose unit.

Histidine biosynthesis is carefully regulated by feedback inhibition/[11] R5P can be converted to adenosine diphosphate ribose, which binds and activates the TRPM2 ion channel.

[16] The build up is caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT), which leads to decreased nucleotide synthesis and an increase of uric acid production.